Control system



June 18, 1935. L. J. KOCI CONTROL SYSTEM Filed Nov. 12, 1951 Patented June 18, 1935 UNITED STATES PATENT OFFICE CONTROL SYSTEM Application November 12, 1931, Serial No. 574,585

1 Claim.

This invention relates to a control system and more particularly to a system for controlling the position of an element with respect to another element mechanically unconnected therewith.

An object of the invention is to provide a simple and effective control system.

In many types of furnaces, such as gas-fired furnaces, the temperature regulating means is in some cases adjusted manually in accordance with a temperature indicating means. If the temperature, for instance, is too low the fuel input is increased. However, it is extremely difficult to judge how much to adjust the fuel input in order to bring the furnace to the desired temperature 5 and if it is found that the temperature passes beyond the desired value, the control must again be adjusted to reduce the temperature. It may also be necessary to adjust the fuel input to compensate for varying loads onthe furnace.

In accordance with one embodiment of an apparatus illustrating the invention, a movable member is attached to a recording thermometer and the position of a valve mechanically unconnected with the movable member is controlled by the position of the movable member.

The single figure of the drawing is a schematic view of an apparatus embodying the invention.

Referring now more in detail to the drawing, a recording thermometer 5 is shown having a segmental contact member 6 attached to the end of shaft 1, which is an extension of the shaft for adjusting the position of recording pencil 8. This recording thermometer may be of any well known type, such asthe recording thermometer 5 disclosed in the patent to Brewer No. 1,356,804, October 26, 1920. The segmental member 6 has a plurality of segments 9 which are substantially equal in width and separated by insulating sections I l which are slightly wider than a brush I2 40 contacting with the member. The end segments l3 and I come into play for lower and higher temperatures than the intermediate sections 9 which cover the normal range. Segments l3 and II complete an annulus with segments 9 and are 45 separated by an insulating section I5.

Motor 16 carries a segmental member I! on its shaft ID. This segmental member has segments I9, corresponding to the segments 9 of segmental member 8, and at the ends of these 50 segments are segments 2| and 22 for low and high temperatures, respectively, corresponding to segments l3 and I4 of segmental member 8. The segments 2| and 22 are substantially the same width as segments I9 and the annulus is com- 55 pleted by along segment 23 of insulating material.

The member H has a pair of elongated arcuate brushes 24 and 25, the ends of which are spaced apart slightly more than the width of one of the segments on this member. The segments 9, l3 and M are electrically connected to segments l9, 2| and 25 by conductors 26.

Motor i6 is provided with an armature winding 21 and a pair of field windings 28 and 23. Brush 2 is connected to one of the commutator brushes of the motor through the armature winding, to the other commutator brush and to a terminal member 3|. The brushes 24 and 25 are connected through field windings 28 and 29, respectively, to the terminal member 32. The motor is a series motor and the field windings are so arranged that when one of the field windings is energized, the motor will rotate in one direction and when the other field winding is energized, the motor will rotate in the opposite direction. The motor shaft l0 carries a cam 33 engaging a stem 34 of valve 35 which controls the fuel to the furnace, the temperature of which is recorded by the recording thermometer 5.

The operation of the apparatus is as follows:

-In the position shown the temperature of the furnace is at the proper value and brush l2 rests on the first segment 9. If the temperature of the furnace increases, the segmental member 6 will rotate in a clockwise direction, as viewed in the figure, and cause the segment It to move under brush 2. This closes a circuit which may be traced from terminal member 3| through the armature winding to brush I2, segment l4, segment 22, brush 25, and in series through the field winding 29 to terminal member 32. The motor will thus be energized in such a direction as to close the valve 35 and at the same time cause segmental member I! to move in such a direction as to cause the segment 22 to move to a position between brushes 24 and 25, thus breaking the circuit and stopping the motor. In a similar manner the motor is energized to rotate in the opposite direction to that just described when the second segment 9 moves under brush 2. The reason for the motor rotating in the opposite direction in this case is that when the second. segment 9 contacts with brush l2 in going from the position shown in the' drawing, contact will be made with brush 24 and field winding 28, thereby energizing the motor to operate in an opposite direction from that in which it operates when the circuit is completed through brush 25 and field winding 29.

It is evident that the degree of fineness of adjustment of valve 35 may be varied at will by inature, a cam for actuating said valve, a motor for actuating the cam, a contact member carried by said motor having a plurality 01 segments, a contact member actuated by said temperature responsive means having a plurality of segments, and circuit connections between segments or said contact members and the motor for causing the motor to directly position the cam in accordance with the position of the segments of the contact member actuated by the temperature responsive 10 means.

LUDVIK JOSEPH KOCI. 

